What causes cataracts?

We have previously talked a little bit about cataracts. However, a common question that comes up is what causes the cataract. The lens is made up of a number of proteins that are aligned in a uniform fashion. This uniform alignment allows light to pass through the lens of the eye without being scattered. However, the lens continues to grow throughout life from cells growing mainly from the equator of the lens. These fibers continue to compress the lens over time. Clinically, the ophthalmologist or eye doctor will see the center of the lens as less clear. The lens is kind of like a peanut M&M or the core of the earth. The central part called the nucleus tends to become denser and more opaque with this compression. This corresponds to the loss of clarity by many of these lens proteins losing their uniform nature. The lens will go from clear, to yellow, to darker yellow, and finally to brown or red. This opacity manifests as blurred vision, difficulty seeing in the dark, and a loss in the "sharpness" of vision. This type of cataract is called a nuclear sclerotic form of cataract and it is essentially unavoidable with age. It occurs at different rates, but everyone will get this type of age-related cataract if they live long enough. Typically this becomes a factor in the 70s or early 80s, but I have had a patient that did not have a significant problem with this until age 100 when I performed her surgery. There are other types of cataracts also. Some cataracts can form from trauma to the eye; they can come on rapidly or they can develop over time after the initial injury. They can cause a clouding of the outer layer of the lens called the cortex. This clouding can also occur naturally with time when they fibers precipitate. These cataracts are often white and a cortical cataract can cause severe glare as it becomes established. Problems with metabolism can also cause cataracts. Diabetics and smokers are prone to early cataracts, but cataracts can be rapid in onset with poorly controlled diabetes. In these patients, the cataract will be filled with sugar from the blood and it will cause the fibers to rapidly swell, and a severe cataract can occur overnight. Diabetics are also prone to posterior subscapsular cataracts. These are cataracts that are plastered in small cysts to the back layer of the lens. They usually cause severe glare and can develop over a short period of time. There are other cataracts that can be associated with congenital infections such as rubella and toxoplasmosis. Others are genetic at birth, whereas others occur in conditions in adulthood such as myotonic dystrophy which causes a "Christmas tree" cataract as pictured above. The good news is that most cataracts can be surgically removed regardless of their etiology. If you are interested in cataract surgery, you can call our office to schedule an evaluation with Dr. Aaker.